Implant gun

ABSTRACT

Subcutaneous implant gun for dispensing pellets comprises case with hollow needle attached thereto. Plunger in alignment with hollow needle reciprocates to expell pellets through needle as pellets are positioned in path of plunger travel. Reciprocable bushing in alignment with hollow needle supportingly surrounds plunger. Trigger pivoted to case is connected to reciprocable bushing and plunger, and linkage system between trigger and bushing and plunger causes bushing and plunger to move in direction of hollow needle when trigger is depressed. Bushing and plunger move away from hollow needle when trigger is released.

United States Patent Wyatt et al.

[54] IMPLANT GUN [72] Inventors: James B. Wyatt, Stamford; Peter D.George, Easton; Kenneth Van Dyck,

Weston, all of Conn.

[ 73] Assignee: Pfizer Inc., New York, N. Y. [22] Filed: June 15,1970[2|] Appl.No.: 46,159

[52] U.S.Cl. ..l28/217 s1 Int.Cl. ...A61ms/00 [58] FieldofSeareh8/217,264

[56] References Cited UNITED STATES PATENTS 3,520,299 7/1970 Lottetal....i ...128/2l7 3,402,712 9/1968 Eisenhand ..128/217 2,883,984- 4/1959Candidoetal ..l28/217 [151 3,669,104 [451 June 13, 1972 FOREIGN PATENTSOR APPLICATIONS 272,445 1963 Australia 128/21 7 253,175 1964 Australia..l28/2l7 472,560 1937 Great Britain 128/217 Primary Examinerbouis G.Mancene Assistant Examiner-D. L. Weinhold Anorney--Connolly and Hutz[57] ABSTRACT Subcutaneous implant gun for dispensing pellets comprisescase with hollow needle attached thereto. Plunger in alignment withhollow needle reciprocates to expell pellets through needle as pelletsare positioned in path of plunger travel.

Reciprocable bushing in alignment with hollow needle supportinglysurrounds plunger. Trigger pivoted to case is connected to reciprocablebushing and plunger, and linkage system between trigger and bushing andplunger causes bushing and plunger to move in direction of hollow needlewhen trigger is depressed. Bushing and plunger move away from hollowneedle when trigger is released.

6 Claims, 7 Drawing Figures BACKGROUND OF THE INVENTION The presentinvention relates to an implant gun, and more particularly to asubcutaneous implant gun for dispensing pellets through a hollow needlefrom the magazine of a cartridge holding a plurality of pellets.

In the past, numerous implant gun constructions have been proposed fordispensing solid pellet material. Many of these heretofore proposedconstructions are characterized by their complex and inefiicient mode ofoperation as well as the unusually large number of parts required toconstruct them. In many instances, the moving parts of these implantguns tend to wear out very rapidly thereby rendering the constructionsuseless. Jamming is also a problem.

Accordingly, it is an object of the present invention to provide asimple and easy-to-use implant gun which functions in a highlydependable and trouble-free manner to dispense implant pellets from acartridge holding a plurality of pellets.

SUMMARY OF THE INVENTION In accordance with the present invention, asubcutaneous implant gun for dispensing pellets comprises a case with ahollow needle attached to the front portion of the case. A reciprocableplunger is in alignment with the hollow needle for expelling pelletsthrough the hollow needle as the pellets are positioned in the path ofplunger travel. A reciprocable bushing also in alignment with the hollowneedle supportingly surrounds the plunger. A trigger pivoted to the caseis connected to reciprocate the bushing and the plunger. A linkagesystem connected between the trigger and the bushing and plunger causesthe bushing and plunger to move in the direction of the hollow needlewhen the trigger is depressed. The plunger moves away from the hollowneedle when the trigger is released.

The forward end of the bushing adjacent the hollow needle may bechamfered. Moreover, a cartridge holder can be positioned between thehollow needle and the bushing for accommodating a cartridge containing aplurality of implant pellets. Preferably, the case of the implant gunincludes a pair of tracks that parallel the path of travel of theplunger. Pins connected to the plunger are positioned in the tracks forsupporting the plunger as it reciprocates along its path of travel.

The linkage system may include a cam link pivotally connected to thecase having a cam track thereon. A first connected link between thetrigger and the cam link rotates the cam link about its pivotalconnection when the trigger is manipulated. A second connector linkbetween the cam link and the plunger reciprocates the plunger along itspath of travel as the cam link rotates. A bell crank pivotally connectedto the case has a cam follower at one end thereof that engages the camtrack on the cam link for rotating the bell crank as the cam linkrotates. The other end of the bell crank is connected to the bushing forreciprocating the bushing along its path of travel as the ball crankrotates.

BRIEF DESCRIPTION OF THE DRAWING Novel features and advantages of thepresent invention in addition to those mentioned above will becomeapparent to those skilled in the art from a reading of the followingdetailed description in conjunction with the accompanying drawingwherein:

FIG. 1 is a top plan view of a subcutaneous implant gun according to thepresent invention;

FIG. 2 is a side elevational view of the implant gun illustrated in FIG.1;

FIG. 3 is a front elevational view of the implant gun illustrated inFIGS. 1 and 2;

FIG. 4 is a top plan view of the subcutaneous implant gun shown in FIGS.1-3 with the upper half of the gun case removed and portions broken awayto show interior details;

FIG. 5 is a view similar to FIG. 4 illustrating one stage in thesequence of operation of the implantgun according to the presentinvention;

FIG. 6 is a view similar to FIGS. 4 and 5 illustrating still anotherstage in the sequence of operation of the implant gun according to thepresent invention; and

FIG. 7 is a sectional view taken along line 77 of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION In accordance with the presentinvention, a subcutaneous implant gun 10 comprises a case 12 includingan upper half 14 and a lower half 16 releasably secured together bymachine screws 18. The gun case halves are shaped to provide a cavity 20for holding mechanisms that dispense implant pellets of solid materialfrom the rotary magazine of a cartridge 22 containing a plurality ofsuch pellets. The cartridge 22 is releasably secured to a cartridgeholder 24 arranged to accommodate the cartridge. A hollow needle 26 isfixed to a collet 28 on the cartridge holder by a collet nut 30.

The structural relationship between the cartridge 22 and the cartridgeholder 24 is suchthat the implant pellets held by the rotary magazine ofthe cartridge 22 are in alignment with the hollow needle 26 as themagazine is caused to rotate within the cartridge case. As explained indetail in copending application Ser. No. 633,886, filed Apr. 26, 1967,now US. Pat. No. 3,520,299, the cartridge 22 includes an integrallyhinged activator element 32 that operates to advance the magazineimmediately prior to the dispensing of an implant pellet. For thepurpose of this application it is sufficient to state that when theactivator element 32 of the cartridge 22 is flexed about its integralhinge or in other words urged upwardly as viewed in FIGS. 4-6, themagazine of the cartridge is caused to rotate a sufficient distance soas to position the next implant pellet to be dispensed at a location fordispensing. After that pellet is dispensed and just prior to the nextdispensing operation the activator element 32 is again flexed about itsintegral hinge to thereby position the next pellet in the magazine at alocation for dispensing.

As indicated above, the upper and lower halves of the gun case 12provide a cavity 20 for housing the mechanisms that accomplish thepellet dispensing operation. A bridge plate 34 is secured to the lowerhalf 16 of the gun case 12 by machine screws 36. The bridge plate isfixed relative to the gun case 12 and includes a pair of pivot mountingpoints, for purposes explained below. A cam link 38 is pivoted to thebridge plate 34 at one of the two pivot points on the plate by a pivotpin 40. The cam link 38 has a cam track 42 the function of which isexplained below. One end of the cam link is pivotally connected to ayoke link 44 which in turn is pivotally connected to one end of areciprocable push rod or plunger 46 by a swivel 48. The push rod orplunger 46 reciprocates along a path of travel in alignment with thehollow needle 26. As

shown best in FIGS. 5 and 7, the swivel 48 includes a pair of stud rods50 which extend outwardly therefrom and ride in tracks 52 formed in theupper and lower halves of the gun case 12. This arrangement assists incontrolling the path of travel of the plunger 46 as well as supportingthe plunger as it reciprocates. The plunger 46 has a pair oflongitudinally oriented grooves or channels 53 that prevent jamming dueto accumulated pellet dust inside the bushing 62. Without such groovesdust can easily accumulate between the bushing and the plunger and causejamming.

A bell crank 54 is pivotally connected to the bridge plate 34 at theother of its pivot points by pivot pin 56. One end of the bell crank 54carries a cam follower 58 which rides in the cam track 42 on the camlink 38. As explained more fully below, as the cam link 38 is caused torotate about the cam link pivot pin 40, the cam follower 58 on the bellcrank 54 rides in the cam track 42 of the link 38 to thereby cause thebell crank 54 to rotate about its pivot 56. The end of the bell crank 54opposite the cam follower 58 is pivotally attached to a twist link 60which in turn is secured to a reciprocable bushing 62. Movement of thebell crank 54 about its pivot pin 56 causes the bushing 62 toreciprocate along a path of travel in alignment with the hollow needle26. As the bushing moves outwardly from the gun case 12 a forwardchamfered end portion 64 engages the activator element 32 of the implantcartridge 22. As explained more fully below, continued outward move mentof the bushing 62 flexes the activator element 32 about its integralhinge to advance the rotary magazine of the cartridge 22. As shown bestin FIGS. 4-6, the bushing 62 supportingly surrounds the plunger 46 atthe end of the plunger opposite its connection to the yoke link 44.

A trigger 68 pivoted to the gun case 12 by a pivot pin 70 is providedfor reciprocating the plunger 46 and the bushing 62. The trigger 68 ispivotally connected to the cam link 38 by an arcuate shaped connectorlink 72, as shown best in FIGS. 4-6. As viewed in FIGS. 46, when thetrigger 68 is depressed into the gun case 12, the cam link 38 is causedto rotate in a counterclockwise direction about its pivot pin 40. Therotating cam link rotates the bell crank 54 in the same direction.Together, the cam link and bell crank cause the plunger 46 and bushing62 to move outwardly from the gun case 12 to accomplish the dispensingoperation in the manner explained below.

A coil spring 74 positioned between a spring seat 75 on the trigger 68and a spring seat 76 on case half 16 operates to return the trigger 68to its starting position outwardly of the gun case 12. Fixed stops 78and 80 are provided to limit the movement of the trigger and cam link,respectively. A lip 82 on the trigger 68 limits the outward movement ofthe trigger by engaging the case 12, as shown in FIGS. 4-6.

With a full cartridge 22 positioned within the cartridge holder 24, thesequence of operation of the subcutaneous implant gun is as follows.First, the trigger 68 is depressed thereby causing it to rotate aboutits pivot pin 70 into the gun case 12. Such movement places the arcuateconnector link 72 under tension and causes that link to rotate the camlink 38 in a counterclockwise direction, as viewed in FIGS. 4-6. Themotion of the cam link 38 is transmitted to the bell crank 54 via thecam track 42 and the cam follower 58 on the bell crank. The first fewdegrees of rotation of the cam link 38 operate to urge the bell crank 54to the full extent of its counterclockwise rotary motion. Continuedrotation of the cam link does not cause the bell crank to rotate. Themotion of the bell crank is transmitted to the bushing 62 by the twistlink 60. This movement urges the bushing from the position shown in FIG.4 to the position shown in FIG. 5. The forward chamfered portion 64 ofthe bushing 62 slides across the inclined surface of the activatorelement 32 of the cartridge 22 to flex the activator about its integralhinge and thereby rotate the magazine of the cartridge to position animplant pellet in the path of plunger travel which path is in alignmentwith the hollow needle 26.

The plunger 46 and the busing 62 move together as the trigger 68 isdepressed inwardly into the gun case 12. However, the plunger does notemerge from the bushing until after the activator element 32 has beenflexed out of the path of plunger travel. With the activator element outof the way of the plunger continued inward movement of the trigger 68about its pivot pin 70 urges the plunger 46 through the pelletcontaining opening in the rotary magazine of the cartridge 22 and intothe hollow needle 26. Ultimately, the plunger is positioned as shown inFIG. 6 and the implant pellet being dispensed is expelled through an outof the hollow needle 26. The trigger 68 is then released and the coilspring 74 returns the trigger to its starting position. Since thetrigger is connected to the plunger 46 through the arcuate connectorlink 72, the cam link 38, and the yoke link 44 the plunger is returnedto its starting position along with the trigger. When the trigger isreleased the clockwise rotation of the cam link 38, as viewed in FIGS.4-6, ultimately causes the bell crank 54 to rotate in a similardirection. Such rotation of the bell crank is transmitted to the bushing62 through the twist link 60 and the bushing returns to its startingposition shown in FIG. 4. The implant gun 10 is then ready to dispensethe next implant pellet in the magazine of the cartridge 22.

WHAT IS CLAIMED IS:

1. A subcutaneous implant gun for dispensing pellets comprising a casewith a hollow needle attached thereto, a reclprocable plunger inalignment with the hollow needle for expelling pellets through thehollow needle as they are positioned in the path of plunger travel, areciprocable bushing in alignment with the hollow needle supportinglysurrounding the plunger, both the plunger and the bushing beingreciprocable along a path in alignment with the hollow needle, a triggerpivoted to the case connected to reciprocate the bushing and theplunger, and a linkage system connected between the trigger and thebushing and plunger for causing the bushing and plunger to move in thedirection of the hollow needle when the trigger is depressed and theplunger away from the hollow needle when the trigger is released.

2. A subcutaneous implant gun as in claim 1 wherein the forward end ofthe bushing adjacent the hollow needle is chamfered.

3. A subcutaneous implant gun as in claim 1 wherein the linkage systemincludes a cam link pivotally connected to the case having a cam trackthereon, a first connector link between the trigger and the cam link forrotating the cam link about its pivotal connection when the trigger ismoved, a second connector link between the cam link and the plunger forreciprocating the plunger along its path of travel as the cam linkrotates, a bell crank pivotally connected to the case, one end of thebell crank having a cam follower that engages the cam track on the camlink for rotating the bell crank as the cam link rotates, and meansconnecting the other end of the bell crank to the bushing forreciprocating the bushing along its path of travel as the bell crankrotates.

4. A subcutaneous implant gun as in claim 3 wherein the trigger isspring biased away from the case whereby when the trigger is released itmoves outwardly from the case and withdraws the plunger away from thehollow needle.

5. A subcutaneous implant gun as in claim 1 including a cartridge holderpositioned between the hollow needle and the bushing arranged toaccommodate a cartridge containing a plurality of implant pellets.

6. A subcutaneous implant gun as in claim 1 wherein the case includes apair of tracks that parallel the path of travel of the plunger, and pinsconnected to the plunger and positioned in the tracks for supporting theplunger as it reciprocates along its path of travel.

1. A subcutaneous implant gun for dispensing pellets comprising a casewith a hollow needle attached thereto, a reciprocable plunger inalignment with the hollow needle for expelling pellets through thehollow needle as they are positioned in the path of plunger travel, areciprocable bushing in alignment with the hollow needle supportinglysurrounding the plunger, both the plunger and the bushing beingreciprocable along a path in alignment with the hollow needle, a triggerpivoted to the case connected to reciprocate the bushing and theplunger, and a linkage system connected between the trigger and thebushing and plunger for causing the bushing and plunger to move in thedirection of the hollow needle when the trigger is depressed and theplunger away from the hollow needle when the trigger is released.
 2. Asubcutaneous implant gun as in claim 1 wherein the forward end of thebushing adjacent the hollow needle is chamfered.
 3. A subcutaneousimplant gun as in claim 1 wherein the linkage system includes a cam linkpivotally connected to the case having a cam track thereon, a firstconnector link between the trigger and the cam link for rotating the camlink about its pivotal connection when the trigger is moved, a secondconnector link between the cam link and the plunger for reciprocatingthe plunger along its path of travel as the cam link rotates, a bellcrank pivotally connected to the case, one end of the bell crank havinga cam follower that engages the cam track on the cam link for rotatingthe bell crank as the cam link rotates, and means connecting the otherend of the bell crank to the bushing for reciprocating the bushing alongits path of travel as the bell crank rotates.
 4. A subcutaneous implantgun as in claim 3 wherein the trigger is spring biased away from thecase whereby when the trigger is released it moves outwardly from thecase and withdraws the plunger away from the hollow needle.
 5. Asubcutaneous implant gun as in claim 1 including a cartridge holderpositioned between the hollow needle and the bushing arranged toaccommodate a cartridge containing a plurality of implant pellets.
 6. Asubcutaneous implant gun as in claim 1 wherein the case includes a pairof tracks that parallel the path of travel of the plunger, and pinsconnected to the plunger and positioned in the tracks for Supporting theplunger as it reciprocates along its path of travel.